In recent years, children’s mental health problems, including Attention Deficit Hyperactivity Disorder (ADHD), have been a growing phenomenon. However, there are limited examples of designing for and with children with ADHD. This work views conditions such as ADHD through the lens of neurodiversity as different cognitive styles, focusing on “coolabilities” and enhanced competences instead of disabilities. This paper explores how to engage children with ADHD in co-design activities. Taking the Diversity for Design (D4D) framework as a starting point, an adaptation of the framework for ADHD was first driven by theoretical considerations and three expert interviews, followed by an empirical study consisting of three co-design workshops with four male participants (aged 7–10). Based on observations and audio recordings from the co-design workshops, a qualitative analysis was carried out. Our results show that when their needs, preferences, and individual desires are taken into account, children with ADHD can be meaningfully engaged in co-design activities. By offering an adapted version of the D4D framework tailored for ADHD, designers can structure the environment and provide scaffolds so that children with ADHD can become active participants in co-design workshops. This research informs the design community on how to engage and involve children with ADHD into the design process.